The present invention relates to refrigerated merchandisers and, more particularly, to glass doors for refrigerated merchandisers.
Refrigerated merchandisers generally include a case defining a product display area for supporting and displaying food products to be visible and accessible through an opening in the front of the case. Refrigerated merchandisers are generally used in retail food store applications such as grocery or convenient stores or other locations where food product is displayed in a refrigerated condition. Some refrigerated merchandisers include doors to enclose the product display area of the case and reduce the amount of cold air released into the surrounding environment. The doors typically include one or more glass panels, allowing a consumer to view the food products stored inside the case.
Refrigerated merchandisers may be susceptible to condensation forming on the glass panel of the door, which obstructs viewing of the food product positioned inside the case. Condensation typically forms on the outer surface of the glass panel due to a cool outer surface being in communication with the ambient environment. In addition, fog can form on the inside surface of the panel due to the inner surface generally being in communication with the relatively cold product display area and then being exposed to the relatively humid air of the ambient environment when the door is opened.
Some existing doors use a high-wattage heated coating applied to an inner surface of the glass panel that is in communication with the surrounding environment to inhibit or remove condensation on the outermost surface of the door. Similar high-wattage heated coatings are typically used on the glass panel that is adjacent the product display area to inhibit or remove fog on the innermost surface of the door. These conventional doors often use a relatively high amount of heat energy (e.g., 200 Watts, 300 Watts, etc.) to remove condensation and fog on the innermost and outermost surfaces of the door. The high amounts of heat energy used with these doors are generally needed to overcome heat losses associated with heating portions of the door in addition to heating the glass panel.
Other existing doors do not use heat energy to limit formation of condensation on the door. Instead, these doors use a single silver low-emissivity coating on the outermost surface of the glass panel to limit formation of condensation on the outermost surface of the door. Fog often forms on the innermost surface of these doors without heat energy applied to the door. In addition, the timeframe for removing condensation and fog from the door increases after a door opening event due to a lack of heat energy applied to the door.